3,882 research outputs found
Synthesis optimization and charge carrier transfer mechanism in LiLuSiO<sub>4</sub>:Ce, Tm storage phosphor
No full textLiLuSiO4:Ce and LiLuSiO4:Ce, Tm show very efficient charge carrier storage properties upon beta irradiation after samples have received treatment in vacuum. They outperform the commercial storage phosphor BaFBr(I):Eu2+ in many aspects. The influence of the synthesis conditions, Ce and Tm concentration, nonstoichiometry and codoping with Ca, Hf, Al and Ge are reported. Based on the results of the synthesis optimization, thermoluminescence (TL) emission and TL excitation spectra a mechanism of charge carrier transfer, storage, and recombination during irradiation and thermal or optical readout is proposed.Accepted Author ManuscriptRST/Fundamental Aspects of Materials and EnergyRST/Luminescence Material
GA Landsat 5 TM Analysis Ready Data Collection 3
No full textMaintenance and Update Frequency: asNeededStatement: This product is derived from the USGS Landsat Collection 1 archive.
The Moderate Resolution Imaging Spectroradiometer (MODIS) MCD43A1 Version 6 Bidirectional Reflectance Distribution Function and Albedo (BRDF/Albedo) Model Parameters dataset was provided by the National Aeronautics and Space Administration (NASA). It was produced daily using 16 days of Terra and Aqua MODIS data at 500 m resolution.
The ozone data was provided by Environment Canada.
The Aerosol Optical Thickness data was provided by the Commonwealth Scientific and Industrial Research Organisation (CSIRO).
The Precipitable Water for Entire Atmosphere data was provided by the National Oceanic and Atmospheric Administration (NOAA) / Earth System Research Laboratory (ESRL) / Physical Sciences Division (PSD).
The baseline Digital Surface Model (DSM) data produced from the Shuttle Radar Topography Mission (SRTM) was provided by the National Geospatial-Intelligence Agency (NGA).
Level 1 Collection 1 data was provided by the United States Geological Survey (USGS)'s Earth Resources Observation and Science (EROS) Center.<b>BACKGROUND</b><br/><p><br/><p>The United States Geological Survey's (USGS) Landsat satellite program has been capturing images of the Australian continent for more than 30 years. This data is highly useful for land and coastal mapping studies. <br/><p>In particular, the light reflected from the Earth’s surface (surface reflectance) is important for monitoring environmental resources – such as agricultural production and mining activities – over time. <br/><p>We need to make accurate comparisons of imagery acquired at different times, seasons and geographic locations. However, inconsistencies can arise due to variations in atmospheric conditions, sun position, sensor view angle, surface slope and surface aspect. These need to be reduced or removed to ensure the data is consistent and can be compared over time. <br/><p> </p><br/><b>WHAT THIS PRODUCT OFFERS</b><br/><p><br/><p>GA Landsat 5 TM Analysis Ready Data Collection 3 takes Landsat 5 Thematic Mapper (TM) imagery captured over the Australian continent and corrects for inconsistencies across land and coastal fringes. The result is accurate and standardised surface reflectance data, which is instrumental in identifying and quantifying environmental change. <br/><p><br/><p>The TM instrument is an advanced, multispectral scanning, Earth resources sensor which is designed to categorise the Earth's surface. It is particularly useful for agricultural applications and identification of land use. <br/><p><br/><p>This product is a single, cohesive Analysis Ready Data (ARD) package, which allows you to analyse surface reflectance data as is, without the need to apply additional corrections. <br/><p><br/><p>It contains three sub-products that provide corrections or attribution information:<br/><p><br/><p> 1) GA Landsat 5 TM NBAR Collection 3 <br/><p> 2) GA Landsat 5 TM NBART Collection 3<br/><p> 3) GA Landsat 5 TM OA Collection 3<br/><p><br/><p>The resolution is a 30 m grid based on the USGS Landsat Collection 1 archive
The dependence of light extraction improvement on optimized surface microstructure for AlGaN-based UVC-LEDs considering TM-polarized emission
No full textIn order to improve the light extraction of AlGaN-based short wavelength ultraviolet light emitting diodes (DUC-LEDs), a type of microstructure with high aspect ratio is introduced and optimized on the AlN substrate surface. And, particle swarm optimization (PSO) algorithm is used to inverse design of the surface microstructure to maximize the light extraction efficiency (LEE). Considering that the propagation characteristics of TM-polarized light are different from that of TE-polarized light, the optical field distribution and LEE is analyzed for the UVC-LEDs with different TE-polarized component when the optimized surface microstructure is applied. Furthermore, the preparation process tolerance of the high aspect ratio structure is discussed by calculating the LED's LEE when the structural deviation occurs or morphology changes. Simulation results show that, by using the optimized surface microstructure based on parabola cone array, the LEDs' LEE is increased from 4.4% to 8.7% and from 0.4% to 3.7% for TE-polarized and TM-polarized emission, respectively. In addition, it is demonstrated that the light extraction improvement by the surface microstructure has a good tolerance to the structural deviation and morphology. The results are significant for improving light extraction and realizing high efficient short wavelength AlGaN-based UVC-LEDs by designing surface microstructures.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.ImPhys/Esmaeil Zadeh grou
Rigor and relevance in empirical TM research: Key issues and challenges Author links open overlay panel
No full textThis paper aims to offer a critical reflection on the way Talent Management (TM) is investigated in practice, by addressing the key issues regarding the quality (in terms of rigor and relevance) of academic empirical TM research and therefore the critical scrutiny of TM scholars’ work. We will argue that despite the growth in the quantity, the quality of many empirical TM papers is lagging behind and hindering the progress of the academic field of TM. Based on a content analysis of 174 peer-reviewed articles published between 2006 and 2017, the paper outlines nine critical issues regarding the quality of the existent empirical TM research. In order to improve the positioning of the field as well as the impact of TM research on practice itis absolutely necessary for TM scholars to secure the quality of academic empirical TM research. Also, the collaboration between practitioners and scholars should increase.Peer ReviewedPostprint (author's final draft
Rigor and relevance in empirical TM research: Key issues and challenges Author links open overlay panel
No full textThis paper aims to offer a critical reflection on the way Talent Management (TM) is investigated in practice, by addressing the key issues regarding the quality (in terms of rigor and relevance) of academic empirical TM research and therefore the critical scrutiny of TM scholars’ work. We will argue that despite the growth in the quantity, the quality of many empirical TM papers is lagging behind and hindering the progress of the academic field of TM. Based on a content analysis of 174 peer-reviewed articles published between 2006 and 2017, the paper outlines nine critical issues regarding the quality of the existent empirical TM research. In order to improve the positioning of the field as well as the impact of TM research on practice itis absolutely necessary for TM scholars to secure the quality of academic empirical TM research. Also, the collaboration between practitioners and scholars should increase.Peer Reviewe
Dalla Biblioteca Comunale di Urbania: due raccolte musicali per un interprete
No full textIn the Library of Urbania (Marche, Italy) six musical manuscripts containing seventeenth century arias and cantatas are preserved. They belonged to an aristocratic family of Apecchio, (Marche), the Ubaldini. This article investigates two of them containing cantatas by Cossoni, Giovanni Bonaventura Viviani, Legrenzi Bassani and others, and in which there is the note “ex libris Antonij Barbarini”. This article reconstructs the origin of these two manuscripts, for whom the author individuated the probable owner, the singer Ippolito Fusai, by means the repertory identified in it. A thorough investigation of this hitherto little-known manuscripts may shed new light on the diffusion and transmission of music in Italy during the Seventeenth and early-Eighteenth centurie
The Role of the Detergent Micelle in Preserving the Structure of Membrane Proteins in the Gas Phase
No full textDespite the growing importance of the mass spectrometry of membrane proteins, it is not known how their transfer from solution into vacuum affects their stability and structure. To address this we have carried out a systematic investigation of ten membrane proteins solubilized in different detergents and used mass spectrometry to gain physicochemical insight into the mechanism of their ionization and desolvation. We show that the chemical properties of the detergents mediate the charge state, both during ionization and detergent removal. Using ion mobility mass spectrometry, we monitor the conformations of membrane proteins and show how the surface charge density dictates the stability of folded states. We conclude that the gas-phase stability of membrane proteins is increased when a greater proportion of their surface is lipophilic and is consequently protected by the physical presence of the micelle
Membrane proteins bind lipids selectively to modulate their structure and function.
No full textPrevious studies have established that the folding, structure and function of membrane proteins are influenced by their lipid environments and that lipids can bind to specific sites, for example, in potassium channels. Fundamental questions remain however regarding the extent of membrane protein selectivity towards lipids. Here we report a mass spectrometry approach designed to determine the selectivity of lipid binding to membrane protein complexes. We investigate the mechanosensitive channel of large conductance (MscL) from Mycobacterium tuberculosis and aquaporin Z (AqpZ) and the ammonia channel (AmtB) from Escherichia coli, using ion mobility mass spectrometry (IM-MS), which reports gas-phase collision cross-sections. We demonstrate that folded conformations of membrane protein complexes can exist in the gas phase. By resolving lipid-bound states, we then rank bound lipids on the basis of their ability to resist gas phase unfolding and thereby stabilize membrane protein structure. Lipids bind non-selectively and with high avidity to MscL, all imparting comparable stability; however, the highest-ranking lipid is phosphatidylinositol phosphate, in line with its proposed functional role in mechanosensation. AqpZ is also stabilized by many lipids, with cardiolipin imparting the most significant resistance to unfolding. Subsequently, through functional assays we show that cardiolipin modulates AqpZ function. Similar experiments identify AmtB as being highly selective for phosphatidylglycerol, prompting us to obtain an X-ray structure in this lipid membrane-like environment. The 2.3 Å resolution structure, when compared with others obtained without lipid bound, reveals distinct conformational changes that re-position AmtB residues to interact with the lipid bilayer. Our results demonstrate that resistance to unfolding correlates with specific lipid-binding events, enabling a distinction to be made between lipids that merely bind from those that modulate membrane protein structure and/or function. We anticipate that these findings will be important not only for defining the selectivity of membrane proteins towards lipids, but also for understanding the role of lipids in modulating protein function or drug binding
Preferred Reporting Items for the Development of Evidence-based Clinical Practice Guidelines in Traditional Medicine (PRIDE-CPG-TM): Explanation and elaboration
No full textAbstractIntroductionThe development of evidence-based clinical practice guidelines (CPGs) in traditional medicine (TM) is an ongoing challenge as it is unique area. This study describes a unified platform with Preferred Reporting Items for the Development of Evidence-based CPGs in TM (PRIDE-CPG-TM), which has been successfully used by the evidence-based CPGs committee for TM.MethodsInitially we searched the literature and CPG handbooks, collected items from methodology references and drew on experiences gained from Korean medical physicians and methodology experts. A group of experts subsequently edited drafts of the items, identified one or more examples of good reporting for each item, and developed text that explained the rationale and discussed relevant evidence. Face to face meetings were held with experts to finalize the items with the most extensive elaboration.ResultsThe PRIDE-CPG-TM, in the form of a checklist and description of items with TM approach and TM examples, were designed to improve the reporting of CPG in TM and thereby facilitate their interpretation and replication. The PRIDE-CPG-TM included 5 domains and 40 items. The items pertain to the development methodology (22 items), Overview of diseases and symptoms (6 items), Recommendations (4 items), Implementation and dissemination (5 items) and others (3 items).ConclusionsThe completeness of CPG descriptions in TM is very poor. Therefore, a complete description of the recommendations for TM in CPGs is necessary for physicians to implement the recommendations in clinical practice areas. The PRIDE-CPG-TM will provide useful guidance for TM developers in the development of evidence-based CPGs
Study of Tm valence state in CaSi2O2N2 and phosphor-enabled PowerWindow application
No full textPowerWindow is a luminescent solar concentrator which employs a Tm2+-doped material to strongly absorb sunlight and produce a sharp emission in the near-infrared spectrum for energy-harvesting purposes. The absence of self-absorption and the large spectral overlap with the solar spectrum make it an attractive addition to current building-integrated photovoltaics development. Such Tm2+-doped materials have so far been limited to halides that are susceptible to decomposition when exposed to air, which compromises its stability and limits the application. The solutions to functionalize the characteristic Tm2+ photoluminescence properties are two-fold: by an alternative inorganic host (CaSi2O2N2) that is insensitive to moisture, or by using a protective barrier (silicone) that protects halides against decomposition upon exposure to air. The proposed alternative phosphor CaSi2O2N2:Tm is synthesized by solid-state reaction and its luminescent property is examined. The Tm dopant is found to exist in trivalent state (Tm3+) and no luminescence of Tm2+ is found in the material. Besides Tm2O3, different starting powders with other oxidation states (TmI2 and Tm metal powder) were tested to reduce Tm3+ ion to Tm2+ but no change has been observed. It is concluded that the high-lying Tm2+ 4f electronic ground state in CaSi2O2N2 is susceptible to oxidization by losing electrons to its conduction band and therefore unlikely to be stabilized with this synthesis method. The protective barrier approach applied to the NaCl:Tm2+ phosphors was realized by a polydiphenylsiloxane silicone encapsulant. The precursors and the phosphors are cured together in a lamination scheme between two pieces of glass. From the optical properties derived from its absorption and transmission spectra, it is concluded that the Tm2+ valence state of NaCl:Tm2+ is stable in the polymer with no sign of Tm3+ formation at all. While its production process and the relative amount of phosphor still need to be further optimized, a proof-of concept has been attained
- …
